1. Field of the Invention
This invention relates to lasers and is particularly concerned with alignment of lasing cavities, in a ring laser gyroscope for example.
2. Description of the Related Art
Achieving optical alignment of lasing cavities has always been difficult as one mirror, usually a curved mirror, may have to be removed and re-aligned at least once during the building of a lasing cavity or laser. Removal of the mirror and its subsequent re-alignment may result in having to fill the cavity repeatedly with the gain medium and to check the mirror alignment until the correct alignment is achieved. This repetitive procedure increases the risk of scratching sealing faces and the mirror surface as well as introducing contaminants into the clean lasing cavity. Naturally, the problem is worse when triaxial ring laser gyroscopes are being built as each mirror is shared between at least two axes and lasing has to be achieved in three axes simultaneously.